There are cases when a power consumer receiving electric power supplied from an electric power company considers reducing an electricity fee to lower than or equal to a target value. In such cases, the power consumer checks whether the electricity fee is going to exceed the target value, for example, during the electricity fee calculation period (for example, one month). The power consumer takes measures to reduce an amount of consumed electric power, for example, after the power consumer determines that the electricity fee is going to exceed the target value.
Currently, various techniques are known for supporting such measures. For example, Patent Literature 1 discloses a terminal device displaying on a screen a calculation value of an electricity fee from a first day to a current day of a month and a prediction value of the electricity fee in the month.